Microfluidic Droplet‐Based Tailorable Porous GelMA Microspheres for 3D Spatio Controllable Cell Coculture

Abstract For the construction of accurate 3D tissue models in vitro, the 3D coculture model formed by spatio‐controlled distribution of multiple cells is essential. Despite the benefits of porous microspheres with low density, large surface area, and high permeability, exact spatio‐controlled distribution fails to appear in 3D coculture models by using porous microspheres as carriers. Herein, a facile method is proposed to construct a 3D coculture model with heterogeneous cell spatio‐tailored distribution using GelMA microspheres with customizable porosity structure and size based on droplet microfluidics in combination with placeholders. ATPS emulsions, containing two biocompatible immiscible aqueous phases of cell/Alg /dextran (Dex) mixture and polyethylene glycol (PEG) solution, are used as the templates to generate the placeholders. The micron‐sized porous GelMA microspheres are prepared by UV crosslinking of droplets prepared in microfluidic devices, followed by chelation of the placeholders. As a proof of concept, the 3D coculture hepatocellular carcinoma (HCC) model with HepG2 encapsulated outside the pores and HUVEC inside the pores is established. Noteworthy, the cells in the 3D coculture HCC model exhibit greater cell activity and proliferation, enhanced functionalities, and drug resistance than the control group. In conclusion, this straightforward method provides a novel approach for constructing 3D coculture models in vitro.